Aal-'Imran - 3:123

وَلَقَدْ نَصَرَكُمُ اللّهُ بِبَدْرٍ وَأَنتُمْ أَذِلَّةٌ فَاتَّقُواْ اللّهَ لَعَلَّكُمْ تَشْكُرُونَ
[3:123]
And Allah did certainly assist you at Badr when you were weak; be careful of (your duty to) Allah then, that you may give thanks.
Allah had helped you at Badr, when ye were a contemptible little force; then fear Allah; thus May ye show your gratitude.
Allah had already given you the victory at Badr, when ye were contemptible. So observe your duty to Allah in order that ye may be thankful.